RVM is responsible not only for changing Ruby versions, but for installing rubies and managing gemsets, as well.https://robots.thoughtbot.com/using-rbenv-to-manage-rubies-and-gems
...Along with rbenv [to manage ruby versions], we’re using Bundler to manage gems (replacing gemsets) and ruby-build to install rubies.
See also chruby;
Notes: bundler (for resolving deps per Gemfile.lock)
